Usually the flags the MacFarlanes raise reflect their family's New Zealand, Scottish and Northumberland heritage.

But for the past few weeks, passers-by have been able to see the country's new flag options flying.

The flag that New Zealanders opt for this time around will become the country's official flag, if the country votes for change in the second referendum in March.

In this initial postal ballot, voters will be asked to select the contender to replace the incumbent. Voting is not compulsory.

Three of the five flags feature the silver fern. Another depicts the koru, a representation of an unfurling fern frond and the late addition is a flag known as Red Peak, evoking New Zealand's rugged landscapes.

"People have made a special trip round to have a look," Ms MacFarlane said.

"People can just bring a flask of tea with them and park in the paddock and take their time and look at the flags."

"We are very proud and patriotic people but I don't think we display it. And I don't think we use our flag very much," he told the ABC.

"If we had a flag which was much more representative of New Zealand — and by that I personally think the silver fern — then I think people would wear it on shirts, tee-shirts, they'd endorse it and more people would fly it."

The confusion with the Australian flag is another reason Mr Key wants something more distinctly "New Zealand".

"There have been numerous examples where they've either put out the wrong flag or I've been put in front of the wrong flag," he said.

"You only need to go and have a look at the World Cup final at Twickenham to see how close those flags look and difficult for even Kiwis and Australians to see the difference, let alone anyone else who is not familiar with our flags."

He would not be drawn on whether Australia should take the same route, but was adamant it was the right thing for New Zealand.

"I personally think that a change of flag in New Zealand would be much more representative of a young, multicultural society, which obviously has a deep connection and history with its British roots but now is a lot more than just a British colony at the bottom of the world," he said.

For Ms MacFarlane, it is an easy choice — she will be voting for Red Peak.

But as to whether the MacFarlanes think the existing flag should be replaced, tradition, for a family with its own long history, is hard to ignore.

"I was all for a change, and I still wouldn't mind if we accepted the red, white and blue, but I'm pretty happy with what we've got at the moment," Mr MacFarlane said.

And Ms MacFarlane is siding with the incumbent, for now.

"It really depends on which flag is up against the original flag. It would have to be a pretty special flag to put the existing one out in my mind," she said.